/// \file http_parser.cpp
/// Holds all code for the HTTP namespace.

#include "http_parser.h"
#include "util.h"
#include "auth.h"
#include "defines.h"
#include "encode.h"
#include "timing.h"
#include <iomanip>

/// Helper function to check if the given c-string is numeric or not
static bool is_numeric(const char *str){
  while (str[0] != 0){
    if (str[0] < 48 || str[0] > 57){return false;}
    ++str;
  }
  return true;
}

/// Constructor that does the actual parsing
HTTP::URL::URL(const std::string &url){
  IPv6Addr = false;
  // first detect protocol at the start, if any
  size_t proto_sep = url.find("://");
  if (proto_sep != std::string::npos){
    protocol = url.substr(0, proto_sep);
    proto_sep += 3;
  }else{
    proto_sep = 0;
    if (url.substr(0, 2) == "//"){proto_sep = 2;}
  }
  // proto_sep now points to the start of the host, guaranteed
  // continue by finding the path, if any
  size_t first_slash = url.find_first_of("/?#", proto_sep);
  if (first_slash != std::string::npos){
    if (url[first_slash] == '/'){
      path = url.substr(first_slash + 1);
    }else{
      path = url.substr(first_slash);
    }
    size_t hmark = path.find('#');
    if (hmark != std::string::npos){
      frag = Encodings::URL::decode(path.substr(hmark + 1));
      path.erase(hmark);
    }
    size_t qmark = path.find('?');
    if (qmark != std::string::npos){
      args = path.substr(qmark + 1);
      path.erase(qmark);
    }
    if (path.size()){
      if (path[0] == '/'){path.erase(0, 1);}
      size_t dots = path.find("/./");
      while (dots != std::string::npos){
        DONTEVEN_MSG("%s (/./ -> /)", path.c_str());
        path.erase(dots, 2);
        dots = path.find("/./");
      }
      dots = path.find("//");
      while (dots != std::string::npos){
        DONTEVEN_MSG("%s (// -> /)", path.c_str());
        path.erase(dots, 1);
        dots = path.find("//");
      }
      if (path[0] == '/'){path.erase(0, 1);}
      dots = path.find("/../");
      while (dots != std::string::npos){
        size_t prevslash = path.rfind('/', dots - 1);
        if (prevslash == std::string::npos || dots == 0){
          path.erase(0, dots + 4);
        }else{
          path.erase(prevslash + 1, dots - prevslash + 3);
        }
        dots = path.find("/../");
      }
      if (path.substr(0, 2) == "./"){path.erase(0, 2);}
      if (path.substr(0, 3) == "../"){path.erase(0, 3);}
      path = Encodings::URL::decode(path);
    }
  }
  // user, pass, host and port are now definitely between proto_sep and first_slash
  std::string uphp = url.substr(proto_sep, first_slash - proto_sep); // user+pass+host+port
  // Check if we have a user/pass before the host
  size_t at_sign = uphp.find('@');
  if (at_sign != std::string::npos){
    std::string creds = uphp.substr(0, at_sign);
    uphp.erase(0, at_sign + 1);
    size_t colon = creds.find(':');
    if (colon != std::string::npos){
      user = Encodings::URL::decode(creds.substr(0, colon));
      pass = Encodings::URL::decode(creds.substr(colon + 1));
    }else{
      user = Encodings::URL::decode(creds);
    }
  }
  // we check for [ at the start because we may have an IPv6 address as host
  if (uphp[0] == '['){
    // IPv6 address - find matching brace
    IPv6Addr = true;
    size_t closing_brace = uphp.find(']');
    host = uphp.substr(1, closing_brace - 1);
    // continue by finding port, if any
    size_t colon = uphp.find(':', closing_brace);
    if (colon == std::string::npos){
      // no port. Assume default
      port = "";
    }else{
      // we have a port number, read it
      port = uphp.substr(colon + 1);
      if (!is_numeric(port.c_str())){
        host += ":" + port;
        port = "";
      }
    }
  }else{
    //"normal" host - first find port, if any
    size_t colon = uphp.rfind(':');
    if (colon == std::string::npos){
      // no port. Assume default
      port = "";
      host = uphp;
    }else{
      // we have a port number, read it
      port = uphp.substr(colon + 1);
      host = uphp.substr(0, colon);
      if (!is_numeric(port.c_str())){
        IPv6Addr = true;
        host += ":" + port;
        port = "";
      }
    }
  }
  // if the host is numeric, assume it is a port, instead
  if (host.size() && is_numeric(host.c_str())){
    port = host;
    host = "";
  }
  EXTREME_MSG("URL: %s", getUrl().c_str());
}

/// Returns the port in numeric format
uint32_t HTTP::URL::getPort() const{
  if (!port.size()){return getDefaultPort();}
  return atoi(port.c_str());
}

/// Returns the default port for the protocol in numeric format
uint32_t HTTP::URL::getDefaultPort() const{
  if (protocol == "http"){return 80;}
  if (protocol == "https"){return 443;}
  if (protocol == "rtmp"){return 1935;}
  if (protocol == "rtmps"){return 443;}
  if (protocol == "dtsc"){return 4200;}
  if (protocol == "rtsp"){return 554;}
  return 0;
}

/// Returns the file extension of the URL, or an empty string if none.
std::string HTTP::URL::getExt() const{
  if (path.rfind('.') == std::string::npos){
    return "";
  }
  return path.substr(path.rfind('.')+1);
}

/// Returns the full URL in string format
std::string HTTP::URL::getUrl() const{
  std::string ret;
  if (protocol.size()){
    ret = protocol + "://";
  }else{
    ret = "//";
  }
  if (user.size() || pass.size()){
    ret += Encodings::URL::encode(user) + ":" + Encodings::URL::encode(pass) + "@";
  }
  if (IPv6Addr){
    ret += "[" + host + "]";
  }else{
    ret += host;
  }
  if (port.size() && getPort() != getDefaultPort()){ret += ":" + port;}
  ret += "/";
  if (path.size()){ret += Encodings::URL::encode(path, "/:=@[]");}
  if (args.size()){ret += "?" + args;}
  if (frag.size()){ret += "#" + Encodings::URL::encode(frag, "/:=@[]#?&");}
  return ret;
}

/// Returns the full file path, in case this is a local file URI
std::string HTTP::URL::getFilePath() const{
  return "/"+path;
}

/// Returns the URL in string format without auth and frag
std::string HTTP::URL::getProxyUrl() const{
  std::string ret;
  if (protocol.size()){
    ret = protocol + "://";
  }else{
    ret = "//";
  }
  if (IPv6Addr){
    ret += "[" + host + "]";
  }else{
    ret += host;
  }
  if (port.size() && getPort() != getDefaultPort()){ret += ":" + port;}
  ret += "/";
  if (path.size()){ret += Encodings::URL::encode(path, "/:=@[]");}
  if (args.size()){ret += "?" + args;}
  return ret;
}

/// Returns the URL in string format without args and frag
std::string HTTP::URL::getBareUrl() const{
  std::string ret;
  if (protocol.size()){
    ret = protocol + "://";
  }else{
    ret = "//";
  }
  if (user.size() || pass.size()){
    ret += Encodings::URL::encode(user) + ":" + Encodings::URL::encode(pass) + "@";
  }
  if (IPv6Addr){
    ret += "[" + host + "]";
  }else{
    ret += host;
  }
  if (port.size() && getPort() != getDefaultPort()){ret += ":" + port;}
  ret += "/";
  if (path.size()){ret += Encodings::URL::encode(path, "/:=@[]");}
  return ret;
}

/// Returns a URL object for the given link, resolved relative to the current URL object.
HTTP::URL HTTP::URL::link(const std::string &l) const{
  // Full link
  if (l.find("://") < l.find('/') && l.find('/' != std::string::npos)){
    DONTEVEN_MSG("Full link: %s", l.c_str());
    return URL(l);
  }
  // Absolute link
  if (l[0] == '/'){
    DONTEVEN_MSG("Absolute link: %s", l.c_str());
    if (l.size() > 1 && l[1] == '/'){
      // Same-protocol full link
      return URL(protocol + ":" + l);
    }else{
      // Same-domain/port absolute link
      URL tmp = *this;
      tmp.args.clear();
      tmp.path = l.substr(1);
      // Abuse the fact that we don't check for arguments in getUrl()
      return URL(tmp.getUrl());
    }
  }
  // Relative link
  std::string tmpUrl = getBareUrl();
  size_t slashPos = tmpUrl.rfind('/');
  if (slashPos == std::string::npos){
    tmpUrl += "/";
  }else{
    tmpUrl.erase(slashPos + 1);
  }
  DONTEVEN_MSG("Relative link: %s+%s", tmpUrl.c_str(), l.c_str());
  return URL(tmpUrl + l);
}

/// This constructor creates an empty HTTP::Parser, ready for use for either reading or writing.
/// All this constructor does is call HTTP::Parser::Clean().
HTTP::Parser::Parser(){
  headerOnly = false;
  Clean();
  std::stringstream nStr;
  nStr << std::hex << std::setw(16) << std::setfill('0') << (uint64_t)(Util::bootMS());
  cnonce = nStr.str();
}

/// Completely re-initializes the HTTP::Parser, leaving it ready for either reading or writing
/// usage.
void HTTP::Parser::Clean(){
  CleanPreserveHeaders();
  headers.clear();
}

/// Completely re-initializes the HTTP::Parser, leaving it ready for either reading or writing
/// usage.
void HTTP::Parser::CleanPreserveHeaders(){
  seenHeaders = false;
  seenReq = false;
  getChunks = false;
  doingChunk = 0;
  bufferChunks = false;
  method = "GET";
  url = "/";
  protocol = "HTTP/1.1";
  body.clear();
  length = 0;
  vars.clear();
}

/// Local-only helper function for use in auth()
/// Returns the string contents of the given val from list
static std::string findValIn(const std::string &list, const std::string &val){
  size_t pos = list.find(val + "=");
  if (pos == std::string::npos){return "";}
  pos += val.size() + 1;
  if (pos >= list.size()){return "";}
  size_t ePos;
  if (list[pos] == '"'){
    ++pos;
    ePos = list.find('"', pos);
    if (ePos == std::string::npos){return "";}
  }else{
    ePos = list.find(',', pos);
  }
  return list.substr(pos, ePos - pos);
}

/// Attempts to send an authentication header with the given name and password. Uses authReq as
/// WWW-Authenticate header.
void HTTP::Parser::auth(const std::string &user, const std::string &pass,
                        const std::string &authReq, const std::string &headerName){
  size_t space = authReq.find(' ');
  if (space == std::string::npos || !user.size() || !pass.size()){
    FAIL_MSG("No authentication possible");
    return;
  }
  std::string meth = authReq.substr(0, space);
  Util::stringToLower(meth);
  if (meth == "basic"){
    SetHeader(headerName, "Basic " + Encodings::Base64::encode(user + ":" + pass));
    return;
  }
  if (meth == "digest"){
    std::string realm = findValIn(authReq, "realm"), nonce = findValIn(authReq, "nonce"),
                opaque = findValIn(authReq, "opaque"), qop = findValIn(authReq, "qop"),
                algo = findValIn(authReq, "algorithm");
    std::string A1 = Secure::md5(user + ":" + realm + ":" + pass);
    if (algo.size() && algo != "MD5"){
      FAIL_MSG("Authorization algorithm %s not implemented", algo.c_str());
      return;
    }
    std::string urlPart;
    if (url.find("://") != std::string::npos && url.substr(0, 4) != "rtsp"){
      HTTP::URL tmpUrl(url);
      urlPart = "/" + tmpUrl.path;
    }else{
      urlPart = url;
    }
    algo = "MD5";
    std::string A2 = Secure::md5(method + ":" + urlPart);
    std::string response;
    static uint32_t nc = 0;
    std::string ncStr;
    if (qop.size()){
      ++nc;
      std::stringstream nHex;
      nHex << std::hex << std::setw(8) << std::setfill('0') << nc;
      ncStr = nHex.str();
      response = Secure::md5(A1 + ":" + nonce + ":" + ncStr + ":" + cnonce + ":auth:" + A2);
    }else{
      response = Secure::md5(A1 + ":" + nonce + ":" + A2);
    }
    std::stringstream rep;
    // username | realm | nonce | digest-uri | response | [ algorithm ] | [cnonce] | [opaque] |
    // [message-qop] | [nonce-count]
    rep << "Digest username=\"" << user << "\", realm=\"" << realm << "\", nonce=\"" << nonce
        << "\", uri=\"" << urlPart << "\", response=\"" << response << "\", algorithm=" + algo;
    if (qop.size()){rep << ", cnonce=\"" << cnonce << "\"";}
    if (opaque.size()){rep << ", opaque=\"" << opaque << "\"";}
    if (qop.size()){rep << ", qop=auth, nc=" << ncStr;}
    SetHeader(headerName, rep.str());
    return;
  }
  FAIL_MSG("No authentication possible, unimplemented method '%s'", meth.c_str());
}

/// Sets the neccesary headers to allow Cross Origin Resource Sharing with all domains.
void HTTP::Parser::setCORSHeaders(){
  SetHeader("Access-Control-Allow-Origin", "*");
  SetHeader("Access-Control-Allow-Credentials", "true");
  SetHeader("Access-Control-Expose-Headers", "*");
  SetHeader("Access-Control-Max-Age", "600");
  SetHeader("Access-Control-Allow-Methods", "GET, POST, OPTIONS, HEAD");
  SetHeader("Access-Control-Allow-Headers", "*");
  SetHeader("Access-Control-Request-Method", "GET");
  SetHeader("Access-Control-Request-Headers", "*");
  SetHeader("Cache-Control", "no-cache, no-store, must-revalidate");
  SetHeader("Pragma", "no-cache");
  SetHeader("Expires", "0");
}

/// Returns a string containing a valid HTTP 1.0 or 1.1 request, ready for sending.
/// The request is build from internal variables set before this call is made.
/// To be precise, method, url, protocol, headers and body are used.
/// \return A string containing a valid HTTP 1.0 or 1.1 request, ready for sending.
std::string &HTTP::Parser::BuildRequest(){
  /// \todo Include POST variable handling for vars?
  std::map<std::string, std::string>::iterator it;
  if (protocol.size() < 5 || protocol[4] != '/'){protocol = "HTTP/1.0";}
  if (method == "GET" && vars.size() && url.find('?') == std::string::npos){
    builder = method + " " + Encodings::URL::encode(url, "/:=@[]") + allVars() + " " + protocol + "\r\n";
  }else{
    builder = method + " " + Encodings::URL::encode(url, "/:=@[]") + " " + protocol + "\r\n";
  }
  for (it = headers.begin(); it != headers.end(); it++){
    if ((*it).first != "" && (*it).second != ""){
      builder += (*it).first + ": " + (*it).second + "\r\n";
    }
  }
  builder += "\r\n" + body;
  return builder;
}

/// Creates and sends a valid HTTP 1.0 or 1.1 request.
/// The request is build from internal variables set before this call is made.
/// To be precise, method, url, protocol, headers and body are used.
void HTTP::Parser::SendRequest(Socket::Connection &conn, const std::string &reqbody, bool allAtOnce){
  /// \todo Include GET/POST variable parsing?
  if (allAtOnce){
    /// \TODO Make this less duplicated / more pretty.

    std::map<std::string, std::string>::iterator it;
    if (protocol.size() < 5 || protocol[4] != '/'){protocol = "HTTP/1.0";}
    builder = method + " " + url + " " + protocol + "\r\n";
    if (reqbody.size()){SetHeader("Content-Length", reqbody.length());}
    for (it = headers.begin(); it != headers.end(); it++){
      if ((*it).first != "" && (*it).second != ""){
        builder += (*it).first + ": " + (*it).second + "\r\n";
      }
    }
    builder += "\r\n";
    if (reqbody.size()){
      builder += reqbody;
    }else{
      builder += body;
    }
    conn.SendNow(builder);
    return;
  }
  std::map<std::string, std::string>::iterator it;
  if (protocol.size() < 5 || protocol[4] != '/'){protocol = "HTTP/1.0";}
  builder = method + " " + url + " " + protocol + "\r\n";
  conn.SendNow(builder);
  if (reqbody.size()){SetHeader("Content-Length", reqbody.length());}
  for (it = headers.begin(); it != headers.end(); it++){
    if ((*it).first != "" && (*it).second != ""){
      builder = (*it).first + ": " + (*it).second + "\r\n";
      conn.SendNow(builder);
    }
  }
  conn.SendNow("\r\n", 2);
  if (reqbody.size()){
    conn.SendNow(reqbody);
  }else{
    conn.SendNow(body);
  }
}

/// Returns a string containing a valid HTTP 1.0 or 1.1 response, ready for sending.
/// The response is partly build from internal variables set before this call is made.
/// To be precise, protocol, headers and body are used.
/// \param code The HTTP response code. Usually you want 200.
/// \param message The HTTP response message. Usually you want "OK".
/// \return A string containing a valid HTTP 1.0 or 1.1 response, ready for sending.
std::string &HTTP::Parser::BuildResponse(std::string code, std::string message){
  /// \todo Include GET/POST variable parsing?
  std::map<std::string, std::string>::iterator it;
  if (protocol.size() < 5 || protocol[4] != '/'){protocol = "HTTP/1.0";}
  builder = protocol + " " + code + " " + message + "\r\n";
  for (it = headers.begin(); it != headers.end(); it++){
    if ((*it).first != "" && (*it).second != ""){
      if ((*it).first != "Content-Length" || (*it).second != "0"){
        builder += (*it).first + ": " + (*it).second + "\r\n";
      }
    }
  }
  builder += "\r\n";
  builder += body;
  return builder;
}

/// Returns a string containing a valid HTTP 1.0 or 1.1 response, ready for sending.
/// The response is partly build from internal variables set before this call is made.
/// To be precise, protocol, headers and body are used.
/// \return A string containing a valid HTTP 1.0 or 1.1 response, ready for sending.
/// This function calls this->BuildResponse(this->method,this->url)
std::string &HTTP::Parser::BuildResponse(){
  return BuildResponse(method, url);
}

/// Creates and sends a valid HTTP 1.0 or 1.1 response.
/// The response is partly build from internal variables set before this call is made.
/// To be precise, protocol, headers and body are used.
/// This call will attempt to buffer as little as possible and block until the whole request is
/// sent. \param code The HTTP response code. Usually you want 200. \param message The HTTP response
/// message. Usually you want "OK". \param conn The Socket::Connection to send the response over.
void HTTP::Parser::SendResponse(std::string code, std::string message, Socket::Connection &conn){
  /// \todo Include GET/POST variable parsing?
  std::map<std::string, std::string>::iterator it;
  if (protocol.size() < 5 || protocol[4] != '/'){protocol = "HTTP/1.0";}
  builder = protocol + " " + code + " " + message + "\r\n";
  conn.SendNow(builder);
  for (it = headers.begin(); it != headers.end(); it++){
    if ((*it).first != "" && (*it).second != ""){
      if ((*it).first != "Content-Length" || (*it).second != "0"){
        builder = (*it).first + ": " + (*it).second + "\r\n";
        conn.SendNow(builder);
      }
    }
  }
  conn.SendNow("\r\n", 2);
  conn.SendNow(body);
}

/// Creates and sends a valid HTTP 1.0 or 1.1 response, based on the given request.
/// The headers must be set before this call is made.
/// This call sets up chunked transfer encoding if the request was protocol HTTP/1.1, otherwise uses
/// a zero-content-length HTTP/1.0 response. \param code The HTTP response code. Usually you want
/// 200. \param message The HTTP response message. Usually you want "OK". \param request The HTTP
/// request to respond to. \param conn The connection to send over.
void HTTP::Parser::StartResponse(std::string code, std::string message, HTTP::Parser &request,
                                 Socket::Connection &conn, bool bufferAllChunks){
  std::string prot = request.protocol;
  sendingChunks =
      (!bufferAllChunks && protocol == "HTTP/1.1" && request.GetHeader("Connection") != "close");
  CleanPreserveHeaders();
  protocol = prot;
  if (sendingChunks){
    SetHeader("Transfer-Encoding", "chunked");
  }else{
    SetHeader("Connection", "close");
  }
  bufferChunks = bufferAllChunks;
  if (!bufferAllChunks){SendResponse(code, message, conn);}
}

/// Creates and sends a valid HTTP 1.0 or 1.1 response, based on the given request.
/// The headers must be set before this call is made.
/// This call sets up chunked transfer encoding if the request was protocol HTTP/1.1, otherwise uses
/// a zero-content-length HTTP/1.0 response. This call simply calls StartResponse("200", "OK",
/// request, conn) \param request The HTTP request to respond to. \param conn The connection to send
/// over.
void HTTP::Parser::StartResponse(HTTP::Parser &request, Socket::Connection &conn,
                                 bool bufferAllChunks){
  StartResponse("200", "OK", request, conn, bufferAllChunks);
}

/// After receiving a header with this object, and after a call with SendResponse/SendRequest with
/// this object, this function call will:
/// - Retrieve all the body from the 'from' Socket::Connection.
/// - Forward those contents as-is to the 'to' Socket::Connection.
/// It blocks until completed or either of the connections reaches an error state.
void HTTP::Parser::Proxy(Socket::Connection &from, Socket::Connection &to){
  if (getChunks){
    unsigned int proxyingChunk = 0;
    while (to.connected() && from.connected()){
      if ((from.Received().size() &&
           (from.Received().size() > 1 || *(from.Received().get().rbegin()) == '\n')) ||
          from.spool()){
        if (proxyingChunk){
          while (proxyingChunk && from.Received().size()){
            unsigned int toappend = from.Received().get().size();
            if (toappend > proxyingChunk){
              toappend = proxyingChunk;
              to.SendNow(from.Received().get().c_str(), toappend);
              from.Received().get().erase(0, toappend);
            }else{
              to.SendNow(from.Received().get());
              from.Received().get().clear();
            }
            proxyingChunk -= toappend;
          }
        }else{
          // Make sure the received data ends in a newline (\n).
          if (*(from.Received().get().rbegin()) != '\n'){
            if (from.Received().size() > 1){
              // make a copy of the first part
              std::string tmp = from.Received().get();
              // clear the first part, wiping it from the partlist
              from.Received().get().clear();
              from.Received().size();
              // take the now first (was second) part, insert the stored part in front of it
              from.Received().get().insert(0, tmp);
            }else{
              Util::sleep(100);
            }
            if (*(from.Received().get().rbegin()) != '\n'){continue;}
          }
          // forward the size and any empty lines
          to.SendNow(from.Received().get());

          std::string tmpA = from.Received().get().substr(0, from.Received().get().size() - 1);
          while (tmpA.find('\r') != std::string::npos){tmpA.erase(tmpA.find('\r'));}
          unsigned int chunkLen = 0;
          if (!tmpA.empty()){
            for (unsigned int i = 0; i < tmpA.size(); ++i){
              chunkLen = (chunkLen << 4) | Encodings::Hex::ord(tmpA[i]);
            }
            if (chunkLen == 0){
              getChunks = false;
              to.SendNow("\r\n", 2);
              return;
            }
            proxyingChunk = chunkLen;
          }
          from.Received().get().clear();
        }
      }else{
        Util::sleep(100);
      }
    }
  }else{
    unsigned int bodyLen = length;
    while (bodyLen > 0 && to.connected() && from.connected()){
      if (from.Received().size() || from.spool()){
        if (from.Received().get().size() <= bodyLen){
          to.SendNow(from.Received().get());
          bodyLen -= from.Received().get().size();
          from.Received().get().clear();
        }else{
          to.SendNow(from.Received().get().c_str(), bodyLen);
          from.Received().get().erase(0, bodyLen);
          bodyLen = 0;
        }
      }else{
        Util::sleep(100);
      }
    }
  }
}

/// Trims any whitespace at the front or back of the string.
/// Used when getting/setting headers.
/// \param s The string to trim. The string itself will be changed, not returned.
void HTTP::Parser::Trim(std::string &s){
  size_t startpos = s.find_first_not_of(" \t");
  size_t endpos = s.find_last_not_of(" \t");
  if ((std::string::npos == startpos) || (std::string::npos == endpos)){
    s = "";
  }else{
    s = s.substr(startpos, endpos - startpos + 1);
  }
}

/// Function that sets the body of a response or request, along with the correct Content-Length
/// header. \param s The string to set the body to.
void HTTP::Parser::SetBody(std::string s){
  body = s;
  SetHeader("Content-Length", s.length());
}

/// Function that sets the body of a response or request, along with the correct Content-Length
/// header. \param buffer The buffer data to set the body to. \param len Length of the buffer data.
void HTTP::Parser::SetBody(const char *buffer, int len){
  body = "";
  body.append(buffer, len);
  SetHeader("Content-Length", len);
}

/// Returns header i, if set.
std::string HTTP::Parser::getUrl(){
  if (url.find('?') != std::string::npos){
    return url.substr(0, url.find('?'));
  }else{
    return url;
  }
}

/// Returns header i, if set.
const std::string &HTTP::Parser::GetHeader(const std::string &i) const{
  if (headers.count(i)){
    return headers.at(i);
  }else{
    static const std::string empty;
    return empty;
  }
}

/// Returns header i, if set.
bool HTTP::Parser::hasHeader(const std::string &i) const{
  return headers.count(i);
}

/// Returns POST variable i, if set.
const std::string &HTTP::Parser::GetVar(const std::string &i) const{
  if (vars.count(i)){
    return vars.at(i);
  }else{
    static const std::string empty;
    return empty;
  }
}

std::string HTTP::Parser::allVars(){
  std::string ret;
  if (!vars.size()){return ret;}
  for (std::map<std::string, std::string>::iterator it = vars.begin(); it != vars.end(); ++it){
    if (!it->second.size()){continue;}
    if (ret.size() > 1){
      ret += "&";
    }else{
      ret += "?";
    }
    ret += it->first + "=" + Encodings::URL::encode(it->second);
  }
  return ret;
}

/// Sets header i to string value v.
void HTTP::Parser::SetHeader(std::string i, std::string v){
  Trim(i);
  Trim(v);
  headers[i] = v;
}

void HTTP::Parser::clearHeader(const std::string &i){
  headers.erase(i);
}

/// Sets header i to integer value v.
void HTTP::Parser::SetHeader(std::string i, long long v){
  Trim(i);
  char val[23]; // ints are never bigger than 22 chars as decimal
  sprintf(val, "%lld", v);
  headers[i] = val;
}

/// Sets POST variable i to string value v.
void HTTP::Parser::SetVar(std::string i, std::string v){
  Trim(i);
  Trim(v);
  // only set if there is actually a key
  if (!i.empty()){vars[i] = v;}
}

/// Attempt to read a whole HTTP request or response from a Socket::Connection.
/// If a whole request could be read, it is removed from the front of the socket buffer and true
/// returned. If not, as much as can be interpreted is removed and false returned. \param conn The
/// socket to read from. \return True if a whole request or response was read, false otherwise.
bool HTTP::Parser::Read(Socket::Connection &conn){
  // Make sure the received data ends in a newline (\n).
  while ((!seenHeaders || (getChunks && !doingChunk)) && conn.Received().get().size() &&
         *(conn.Received().get().rbegin()) != '\n'){
    if (conn.Received().size() > 1){
      // make a copy of the first part
      std::string tmp = conn.Received().get();
      // clear the first part, wiping it from the partlist
      conn.Received().get().clear();
      conn.Received().size();
      // take the now first (was second) part, insert the stored part in front of it
      conn.Received().get().insert(0, tmp);
    }else{
      return false;
    }
  }
  // if a parse succeeds, simply return true
  if (parse(conn.Received().get())){return true;}
  // otherwise, if we have parts left, call ourselves recursively
  if (conn.Received().size()){return Read(conn);}
  return false;
}// HTTPReader::Read

/// Attempt to read a whole HTTP request or response from a std::string buffer.
/// If a whole request could be read, it is removed from the front of the given buffer and true
/// returned. If not, as much as can be interpreted is removed and false returned. \param strbuf The
/// buffer to read from. \return True if a whole request or response was read, false otherwise.
bool HTTP::Parser::Read(std::string &strbuf){
  return parse(strbuf);
}// HTTPReader::Read

/// Checks download completion percentage.
/// Returns zero if that doesn't make sense at the time or cannot be determined.
uint8_t HTTP::Parser::getPercentage() const{
  if (!seenHeaders || length < 1){return 0;}
  return ((body.length() * 100) / length);
}

/// Attempt to read a whole HTTP response or request from a data buffer.
/// If succesful, fills its own fields with the proper data and removes the response/request
/// from the data buffer.
/// \param HTTPbuffer The data buffer to read from.
/// \return True on success, false otherwise.
bool HTTP::Parser::parse(std::string &HTTPbuffer){
  size_t f;
  std::string tmpA, tmpB, tmpC;
  /// \todo Make this not resize HTTPbuffer in parts, but read all at once and then remove the
  /// entire request, like doxygen claims it does?
  while (!HTTPbuffer.empty()){
    if (!seenHeaders){
      f = HTTPbuffer.find('\n');
      if (f == std::string::npos) return false;
      tmpA = HTTPbuffer.substr(0, f);
      if (f + 1 == HTTPbuffer.size()){
        HTTPbuffer.clear();
      }else{
        HTTPbuffer.erase(0, f + 1);
      }
      while (tmpA.find('\r') != std::string::npos){tmpA.erase(tmpA.find('\r'));}
      if (!seenReq){
        seenReq = true;
        f = tmpA.find(' ');
        if (f != std::string::npos){
          if (tmpA.substr(0, 4) == "HTTP"){
            protocol = tmpA.substr(0, f);
            tmpA.erase(0, f + 1);
            f = tmpA.find(' ');
            if (f != std::string::npos){
              url = tmpA.substr(0, f);
              tmpA.erase(0, f + 1);
              method = tmpA;
              if (url.find('?') != std::string::npos){
                parseVars(url.substr(url.find('?') + 1), vars); // parse GET variables
                url.erase(url.find('?'));
              }
              url = Encodings::URL::decode(url);
            }else{
              seenReq = false;
            }
          }else{
            method = tmpA.substr(0, f);
            tmpA.erase(0, f + 1);
            f = tmpA.find(' ');
            if (f != std::string::npos){
              url = tmpA.substr(0, f);
              tmpA.erase(0, f + 1);
              protocol = tmpA;
              if (url.find('?') != std::string::npos){
                parseVars(url.substr(url.find('?') + 1), vars); // parse GET variables
                url.erase(url.find('?'));
              }
              url = Encodings::URL::decode(url);
            }else{
              seenReq = false;
            }
          }
        }else{
          seenReq = false;
        }
      }else{
        if (tmpA.size() == 0){
          seenHeaders = true;
          body.clear();
          if (GetHeader("Content-Length") != ""){
            length = atoi(GetHeader("Content-Length").c_str());
            if (body.capacity() < length){body.reserve(length);}
          }
          if (GetHeader("Content-length") != ""){
            length = atoi(GetHeader("Content-length").c_str());
            if (body.capacity() < length){body.reserve(length);}
          }
          if (GetHeader("Transfer-Encoding") == "chunked"){
            getChunks = true;
            doingChunk = 0;
          }
        }else{
          f = tmpA.find(':');
          if (f == std::string::npos) continue;
          tmpB = tmpA.substr(0, f);
          tmpC = tmpA.substr(f + 1);
          SetHeader(tmpB, tmpC);
        }
      }
    }
    if (seenHeaders){
      if (length > 0){
        if (headerOnly){return true;}
        unsigned int toappend = length - body.length();
        if (toappend > 0){
          body.append(HTTPbuffer, 0, toappend);
          HTTPbuffer.erase(0, toappend);
        }
        if (length == body.length()){
          parseVars(body, vars); // parse POST variables
          return true;
        }else{
          return false;
        }
      }else{
        if (getChunks){
          if (headerOnly){return true;}
          if (doingChunk){
            unsigned int toappend = HTTPbuffer.size();
            if (toappend > doingChunk){toappend = doingChunk;}
            body.append(HTTPbuffer, 0, toappend);
            HTTPbuffer.erase(0, toappend);
            doingChunk -= toappend;
          }else{
            f = HTTPbuffer.find('\n');
            if (f == std::string::npos) return false;
            tmpA = HTTPbuffer.substr(0, f);
            while (tmpA.find('\r') != std::string::npos){tmpA.erase(tmpA.find('\r'));}
            unsigned int chunkLen = 0;
            if (!tmpA.empty()){
              for (unsigned int i = 0; i < tmpA.size(); ++i){
                chunkLen = (chunkLen << 4) | Encodings::Hex::ord(tmpA[i]);
              }
              if (chunkLen == 0){
                getChunks = false;
                return true;
              }
              doingChunk = chunkLen;
            }
            if (f + 1 == HTTPbuffer.size()){
              HTTPbuffer.clear();
            }else{
              HTTPbuffer.erase(0, f + 1);
            }
          }
          return false;
        }else{
          return true;
        }
      }
    }
  }
  return false; // empty input
}// HTTPReader::parse

/// HTTP variable parser to std::map<std::string, std::string> structure.
/// Reads variables from data, decodes and stores them to storage.
void HTTP::parseVars(const std::string &data, std::map<std::string, std::string> &storage){
  std::string varname;
  std::string varval;
  // position where a part starts (e.g. after &)
  size_t pos = 0;
  while (pos < data.length()){
    size_t nextpos = data.find('&', pos);
    if (nextpos == std::string::npos){nextpos = data.length();}
    size_t eq_pos = data.find('=', pos);
    if (eq_pos < nextpos){
      // there is a key and value
      varname = data.substr(pos, eq_pos - pos);
      varval = data.substr(eq_pos + 1, nextpos - eq_pos - 1);
    }else{
      // no value, only a key
      varname = data.substr(pos, nextpos - pos);
      varval.clear();
    }
    if (varname.size()){
      storage[Encodings::URL::decode(varname)] = Encodings::URL::decode(varval);
    }
    if (nextpos == std::string::npos){
      // in case the string is gigantic
      break;
    }
    // erase &
    pos = nextpos + 1;
  }
}

/// Sends a string in chunked format if protocol is HTTP/1.1, sends as-is otherwise.
/// \param bodypart The data to send.
/// \param conn The connection to use for sending.
void HTTP::Parser::Chunkify(const std::string &bodypart, Socket::Connection &conn){
  Chunkify(bodypart.c_str(), bodypart.size(), conn);
}

/// Sends a string in chunked format if protocol is HTTP/1.1, sends as-is otherwise.
/// \param data The data to send.
/// \param size The size of the data to send.
/// \param conn The connection to use for sending.
void HTTP::Parser::Chunkify(const char *data, unsigned int size, Socket::Connection &conn){
  static char hexa[] = "0123456789abcdef";
  if (bufferChunks){
    if (size){
      body.append(data, size);
    }else{
      SetHeader("Content-Length", body.length());
      SendResponse("200", "OK", conn);
      Clean();
    }
    return;
  }
  if (sendingChunks){
    // prepend the chunk size and \r\n
    if (!size){conn.SendNow("0\r\n\r\n", 5);}
    size_t offset = 8;
    unsigned int t_size = size;
    char len[] = "\000\000\000\000\000\000\0000\r\n";
    while (t_size && offset < 9){
      len[--offset] = hexa[t_size & 0xf];
      t_size >>= 4;
    }
    conn.SendNow(len + offset, 10 - offset);
    // send the chunk itself
    conn.SendNow(data, size);
    // append \r\n
    conn.SendNow("\r\n", 2);
  }else{
    // just send the chunk itself
    conn.SendNow(data, size);
    // close the connection if this was the end of the file
    if (!size){
      conn.close();
      Clean();
    }
  }
}

